Telephone-exchange system.



F. N. REEVES. TELEPHONE EXCHANGE SYSTEM. 'APPLICATION msn Nov. 14. 191s.

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by A# y Patented Aug. 7, 1917. Y*

FRANK N. REEVES, OF NEWARK, NEW JERSEY, ASSIGNOR T WESTERN ELECTRIC COM- PANY, INCORPORATED, OF NEW YORK, N. Y., .A CORPORATION OF yNEW' YORK.

TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Patented Aug. '7, 1917.

Applicationled November 14, 1916. Seria1,No..131,230.

To all whom t may concern.'

Y Be it known that I, AFRANK N. REEVES, a citizen of `the United States, residing at Newark, in the county of Essex and State of Newy Jersey, have invented certain new and useful Improvements in Telephone EX- change Systems, of which the yfollowing is a full, clear, concise, andeXact description;

This invention relates to telephone eX- change systems, and moreparticularlylto improvementsin operators listening key vcircuits. In systems in which a multi-.position switch :is used to 4control the connection between the cord :circuit with which said switch is associated and the operators'head set, a timerinterval has been necessary inorder to allow such switch to move intoaitslistening-in position in which the operators head set vis connected to the cord through contacts. of the switch.

It is ythe-object of the present invention to eliminate this time interval.

A feature of the present invention `is thev provision of a relay individual to each cord which will instantly connect the operators Vhead set to the desired cord upon depression of a listening-inkey, additional contacts being provided on the multi-position switch to maintain the connection to the .head set during a certain portion of the movement of such switch.

'Itis thought that the invention will best be understood from the following detailed. description, referenceibeing shad to the accompanying drawing. l p

In'the .part :of the drawing to the .left -of the .dotted .line is yindicated la subscribers substation apparatus, .together `with an. op.-

eratorls lcord circuit and lits Aaccompanying apparatus.V To the right ofthe dotted :line are indicated `portions of a second connecting cord. vIn the dotted. rectangle at .the bottom oi.` the drawing :is indicated. asequenceswitch associated with the .lirstv cord,

while the; dotted rectangle .in .the `upper central portion .of thedrawingshows threexrelays common toall the cordsof anoperators position.

The -subscriberat substation 100 desiring a Vconnection removes his receiver fromthe hookcaus1ng the cnergizationof lm e relay f101.and.the resultant display ofline signall 102 in the well-known manner. The operator, one of whosecords is ndicatedat O,

indicated at K and listening key sequence upon observing the lighting of signal 102, inserts a lplug 103 into'jack 1041 associated with signal 5102, ,whereupon cut-off relay 105 `and relay y106 are energized, relay 105 removing the1control of line relay 101 from 60 the calling subscriber .in the well-known manner. A circuit is now completed from f gEOunded battery, winding ofpower magnet 107 of the listening keysequence switch, lisf tening key sequence switch contact 108,V armature .and fronty contact, of relay 106, -to ground. The' listening'key `sequence switch moves vvfrom position 1 '.to position 7 under the control of its normal contact 109. While thelistening key sequence switch ismoving from positions lto-,6;1, the operators head set 110 .is-.connected tothe desired cordy circuit through listening ;key sequence switchV contacts 1,11 and 112, As soon .as Athe 'listening key sequence switch arrives in position 2 a circuit isV completed from grounded battery, winding of power vmagnet x113.01 the districtsequence switch,:d ist`rict sequence switch contact 114,

listening key sequence switch contact 115,

lthe control of its normalspring l11,6.

Fromposition 51' .to position@ talking bat- 875 teryis edto thecalling subscriber from the repeating coilindicated at C, through listening key sequence switch contacts 117 and 118. When-the listening key sequence switch arrives .in .'position7, conversation between the .operator and the calling subscribermay continue, `the operators head set'ybeingconnectedthrough-,the.armature and back contacts of commonrelay 119, .theringing keys switch contacts 120fand 12.1. .-Atfthis-time talkingv battery is l,fed to the calling subscriber throughy llistening key .sequence switch contacts 122 and 123, keys and listening key sequence .switch contacts 120 and L121'. g Having ascertained the" number of .the wanted line,:the operatori depresses listeningout key LO andV proceedsto set up the desireduconnection in-"the wellknown manner. The depression of the listening-out key completes acircuit fromgrounded battery,wind ingof power magnet :107, listening .key seiquence :switch =contacts124, closed rcontact of key LO, to ground.VA .Tile.listeningfkey se- 11o quence switch thereupon moves out of position 7 and into position 11 under the control of its normal spring 109. 1f the operator does not depress the listening-out key, the listening key sequence switch will be moved out of position 7 as soon as she responds to another call; for instance, if she responds to a call with the cord indicated at the right of the dotted line in the drawing. Then the sequence switch associated with such cord arrives in position 2, a circuit will be completed from grounded battery, windingrof power magnet 107, listening key sequence switch contact 124, common conductor 125, contact 226 of the listening key sequence switch associated with the second cord, to ground, whereupon the first listening key sequence switch will move to its listeningout position as before described. If we assume now that the operator is listening in on the second cord whose sequence switch is therefore in position 7, and that she wishes to again listen in on the lirst cord whose listening key sequence switch is at this time in position 11, she will depress listening-in key LI associated with said iirst cord, whereupon a circuit will be completed from ground, closed contacts of key Ll, through relays 127 and 128 in parallel, listening key sequence switch contact 129, common relay 130, to grounded battery. Relays 127, 128 and 130 will be energized in this circuit, relay 128 completing a locking circuit for these relays at its right-hand armature and front contact, ground now being supplied through district sequence switch contact 131 and the right-hand armature and front contact of relay 128, instead of through the listening-in key contacts. It will be seen therefore, that the listening-in key need only be depressed momentarily.

Relay 130, upon energization, completes a circuit from grounded battery, armature and front contact of relay 130, winding of relay 131, winding of relay 119, to ground. The operation of relay 119 opens the circuit from the operators head set to the cord whose listening-in switch was in position 7, while relay 131 completes a circuit from ground through its armature and front contact, listening key sequence switch contact 224, to the power magnet of the second listening key sequence switch for moving this switch out of position 7 and into position 11.

The operation of relay 127 instantly connects the operators head set to the cord whose listening-in key has been depressed through the armature and front contacts of relay 127, while relay 128 completes a circuit at its left-hand armature from grounded battery, winding of power magnet 107, listening-in sequence switch contact 132, the armature and front contact of relay 128, to ground, for moving this sequence switch out of position 11 and into position 1.

The listening key sequence switch does not stop in position 1 since relay 106 is energized at this time, so that the circuit of power magnet 107 is maintained through listening key sequence switch contact 108 to ground over the same path by which it was rst moved out of its normal position.

When the listening key sequence switch moves out of position 2 contact 129 is opened, with the result that relays 127, 128 and 130 are denergized. Relays 131 and 119 will remain energized unt-il the listening key sequence switch leaves position 6, their energizing circuit extending from grounded battery, listening key sequence switch contact 133, winding of relay 131, winding of relay 119 to ground.

`While the listening key sequence switch is moving from position l to Si, the operators head set is connected to the desired cord circuit through sequence switch contacts 111 and 112 as previously described, and upon arriving in position 7, the listening key sequence switch connects the operators head set to the cord through sequence switch contacts 120 and 121 and the back contacts of relay 119, as previously described.

t will therefore be seen that the operator is instantly connected to the desired cord upon the depression of the listening-in key, and that this connection is maintained over alternate paths until the listening key sequence switch arrives in `position 7 to establish the usual connection. Of the three paths provided for connecting the head set to a cord, one is the usual path provided in the listening-in position of this sequence switch, while the other two auxiliary paths serve to maintain this connection while the switch is passing from its normal to its listening-in position and from its listeningout position to its listening-in position, respectively.

What is claimed is:

1. In a telephone exchange system, a link circuit, a multi-position switch associated with said circuit, an operators telephone set, means including said switch to establish connection between said link circuit and said operators telephone set, auxiliary means associated with said link circuit to establish temporary connection between said circuit and said operators telephone set during movement of said switch means including said switch to enable said operator to reestablish connection between said link circuit and said operators telephone set, and means to operate said auxiliary means during the reconnecting movement of said switch. c

2. In a telephone exchange system, a plurality of subscribers lines, a plurality of link circuits for interconnecting said lines, an operatorls telephone set, a multi-position switch associated with each of said link circuits, means including said switch for connecting said operators telephone set to a link circuit whenever a line is extended thereto, auxiliary means to establish temporary connection between said "telephone set vand said link circuit during the operation of said switch, a manually operable key associated with each of said link circuits, means responsive to a momentary depression of said key to instantly connect said operators telephone set to the link circuit with which said key is associated if such circuit is then in use, and means actuated simul- Y taneously with each new connection of said telephone set to disconnect said telephone set from the link circuit to which it was previously connected. v

3. In a telephone exchange system, a plurality of subscribers lines, an operators position, a plurality of link circuits thereat for interconnecting said lines, an operators telephone set, a multi-position switchassociated with each of said link circuits, means including said switch for connecting said operators telephone set to a link circuit whenever a line is extended thereto, a manually operable key associated withy each of said link circuits, a relay individual to each of said link circuits responsive to a momentary depression o said key to connect said operators telephone set to the link circuit withI which said key is associatedv if such circuit 1s then 1n use, and a relay common to said link circuits actuated simultaneously withV each new kconnection of said telephone, to

disconnect said telephone set from the link circuit to which it was previously connected.

4. In a telephone exchange system, a plurality of subscribers lines, a plurality of ficpies of this patent may be obtained for ve cents each, by addressing th link circuits for interconnecting said lines, an operators telephone set, three electrical paths over any oner of which connection may be established between said telephone set and a desired link circuit, and means to close said -paths at kdesired times.

5. In a telephone exchange system, a plurality of subscribers lines, a plurality of link circuits for interconnecting said lines, a multi-position switch associated Vwith each of said link circuits, an operators telephone set, means for connecting said telephone set l to one of said link circuits through contacts of said switch during a vcertain portion of the movement of said switch, a relay individual to each of said link circuits, means for establishing said' connection through contacts of said relay, a relay common to said link circuits, and means for establishing said connection through other contacts of said switch in one of its resting positions and through contacts `of said common relay.

6. In a telephone exchange system, a line, a link circuit, means for interconnecting said line and said circuit, a movable switch having a normal, a listening-inand a listening-out position, an operators telephone set, means for associating said set with said line when said switch isin its listening-in position, and means for connectingsaid set to said line while said switch is moving from its listening-out to its normal position, and

means for connecting said set to saidy line while said switch is moving from its normal to its listening-in position.

In witness whereof, Iv hereunto subscribe my name this 13th day of November A. D., 1916.

FRANK N. REEVES.

Commissioner of Patents,

l Washington, D. G. Y 

